Mongo atlas image issues

Prerequites

• Docker
• Node

Setup

Install dependencies

npm install

When running mongo in docker, you typically need to mount /data/db as a volume if you want the data to persist across container restarts/removals. However, if you are running the mongodb/mongodb-atlas-local image, you're likely doing so in order to test replicaset behavior, atlas search, or vector search features. In order for those to work across container restarts/removals, you'll need to mound 2 additional volumes:

• /data/configdb
• /data/mongot

However, we've run across some unexpected behavior when you mount those folders.

To reproduce these issues, there are two different setups:

1. Run mongodb/mongodb-atlas-local with the three mounted volumes
2. Run mongodb/mongodb-atlas-local with one mounted volume that encompasses the three folders we need for persistent data.

Issue with Three Mounted Folders

npm run start:3 # Starts the mongo-three-volumes container
node index.js # Prints out list of "messages". Run multiple times and you should see an accumulation of each message inserted.
npm run stop # Stops the docker containers
npm run start:3 # Restarts the mongo-three-volumes container
node index.js # Now this gets a "MongoServerError: not primary"

When looking at the logs for the mongo container, you start to see logs like:

{"t":{"$date":"2024-10-23T16:38:36.723+00:00"},"s":"I",  "c":"-",        "id":4939300, "ctx":"monitoring-keys-for-HMAC","msg":"Failed to refresh key cache","attr":{"error":"ReadConcernMajorityNotAvailableYet: Read concern majority reads are currently not possible.","nextWakeupMillis":3200}}

and

{"t":{"$date":"2024-10-23T16:38:42.733+00:00"},"s":"I",  "c":"SHARDING", "id":7012500, "ctx":"QueryAnalysisConfigurationsRefresher","msg":"Failed to refresh query analysis configurations, will try again at the next interval","attr":{"error":"PrimarySteppedDown: No primary exists currently"}}

To clean up the stored data, run:

npm run clean:3

Issue with Single Mounted Folder

npm run start:1 # Starts the mongo-single-volume container
node index.js # Prints out list of "messages". Run multiple times and you should see an accumulation of each message inserted.
npm run stop # Stops the docker containers
npm run start:1 # Restarts the mongo-single-volume container
node index.js # Messages start over. Data was wiped out.

It seems that mounting /data instead of the /data/db, /data/configdb/ and /data/mongot individually makes mongo delete the data between restarts.

Note

When using the image mongodb/mongodb-atlas-local:7.0.12-20241017T134640Z, the issues seem to go away at least for the 3 mounted folders.